XRPL Sandwich Fears Are Toasty: Schwartz Says Fix Is Two Slices of Fee Away 🥪

Ripple's former Chief Technology Officer David Schwartz has downplayed concerns that the XRP Ledger exposes ordinary traders to sandwich attacks, calling the risk real but overstated while outlining a two-step reservation scheme designed to neutralize front-running on the network's decentralized exchange and automated market maker. The debate was reignited on X after an account argued that validators and well-connected nodes can exploit their view of pending transactions to calculate profitable front-runs and spam the mempool to secure a favorable position in the next ledger's canonical order, worsening slippage for retail users of popular wallets and decentralized applications.

Schwartz, who posted his analysis on June 29, 2026, acknowledged that transaction ordering on the XRP Ledger uses a public, deterministic formula based on transaction hashes, which allows sophisticated actors to position trades ahead of a target. He countered, however, that pending transactions are visible to all participants before each ledger closes, meaning no party holds exclusive early access. "Running a validator does not help you do this unless multiple validators conspire. If multiple validators did conspire, or a single validator attempted it, it would be very obvious to everyone exactly who was doing this and that validator would be immediately removed from everyone's trust lists," Schwartz wrote, noting that validators cryptographically sign all proposals and validations, leaving clear evidence of any collusion.

The ex-CTO also pointed to an economic barrier: profitable sandwich attacks require simultaneously high liquidity, to justify the cost of spamming transactions, and low liquidity, to move the price meaningfully — conditions he said rarely overlap. He added that confirmed sandwich attacks beyond proof-of-concept testing remain unreported to his knowledge, a position consistent with his earlier arguments in XRP Ledger design discussions.

For users seeking stronger guarantees, Schwartz proposed a reservation system in which a trader first broadcasts a reservation specifying a future ledger sequence number, a transaction ID, and a small fee. Once that reservation confirms on the ledger, the actual trade executes before any transaction submitted after the reservation was made public, requiring two submissions per protected trade but eliminating the timing window currently available to front-runners. Schwartz said the proposal complements ongoing institutional privacy work on the XRP Ledger, which addresses related data-layer concerns for payments and offer crossing on the network.